Autoproxy

The Clear Linux* OS is the first Linux distribution to support autoproxy. The OS can discover a Proxy Auto-Config (PAC) script and use it to automatically resolve the proxy needed for a given connection. With Autoproxy, you can use Clear Linux inside any proxy environment without having to manually configure the proxies.

Corporate and private networks can be very complex, needing to restrict and control network connections for security reasons. The typical side effects are limited or blocked connectivity and requiring manual configuration of proxies to perform the most mundane tasks such as cloning a repo or checking for updates. With Clear Linux, all of the work is done behind the scenes to effortlessly use your network and have connections “just work”.

This feature removes massive complications in network connectivity due to proxy issues. You can automate tasks like unit testing without worrying about the proxy not being set and you can remove unset proxies from the equation when dealing with network unavailability across systems.

How Autoproxy works

We designed autoproxy around general tools provided by nearly any Linux distribution with a few minor additions and modifications. We leveraged the DHCP and network information provided from systemd and created a PAC-discovery daemon. The daemon uses the information to resolve a URL for a PAC file. The daemon then passes the URL into PACrunner*. PACrunner downloads the PAC file and uses the newly implemented Duktape* engine to parse it.

From that point on, any cURL* or network requests query PACrunner for the correct proxy to use. We modified the cURL library to communicate with PACrunner over DBus. However, cURL will ignore PACrunner and run normally if no PAC file is loaded or if you set any proxies manually. Thus, your environment settings are respected and no time is wasted trying to resolve a proxy.

More importantly: all these steps happen in the background, very quickly, and with no user interaction.